1. Field of the Invention
This invention relates in general to apparatus and method for t.d.m. frame synchronization at the receiver employing variable synchronizing words and a transmitter produces a t.d.m. signal which consists of groups each consisting of p bits and one marker bit and each multiplex frame contains a total of m marker bits of which s marker bits in each case forms the synchronizing words and at the transmitter the following s-th marker bit is determined by s-1 marker bits and the transmitted signal is transmitted to the receiver and stored in a storage means wherein p+1 addresses are produced which are periodically assigned to the p bits and marker bits of each group and at the receiver the s-th bit is obtained from the s-1 bit stored in the storage means of the t.d.m. signal and compared with the corresponding received bit of the t.d.m. signal and in the vent of identity an identifying pulse is obtained and with successive identifying pulses having the same addresses are counted and depending upon the result of the counting a frame synchronizing signal is emitted with which the receiver t.d.m. frame is set up.
2. Description of the Prior Art
In known prior art processes, individual disturbed marker bits of variable synchronizing words can cause an already established frame synchronization to be thrown out of step and synchronization.